1. Field of the Invention
The present invention relates to a method of manufacturing a device by which a wafer provided with devices formed in a plurality of regions demarcated by planned dividing lines formed in a lattice form in a face-side surface thereof is divided along the planned dividing lines into individual devices and a die-bonding adhesive film is attached to the back side of each of the devices.
2. Description of the Related Art
For example, in the manufacturing process of a semiconductor device, devices such as ICs and LSIs are formed in a plurality of regions demarcated by streets (planned dividing lines) formed in a lattice pattern in the face-side surface of a semiconductor wafer having a roughly circular disk-like shape, and the regions with the devices formed therein are divided along the planned dividing lines, to thereby manufacture the individual devices. As a dividing apparatus for dividing the semiconductor wafer, a cutting apparatus called dicing apparatus is normally used. The cutting apparatus cuts the semiconductor wafer along the planned dividing lines by a cutting blade having a thickness of about 40 μm. The devices divided in this manner are packaged, to be used widely in electric apparatuses such as cellular phones, personal computers, etc.
To the backside surface of each of the devices thus divided individually, a die-bonding adhesive film called die attachment film which is formed of an epoxy resin or the like and having a thickness of 70 to 80 μm is attached, and the device is bonded to a die bonding frame for supporting the device through the adhesive film by heating. The die-bonding adhesive film is attached to the backside surfaces of the devices by, for example, a method in which the adhesive film is adhered to the backside surface of the semiconductor wafer, the semiconductor wafer is adhered to the dicing tape through the adhesive film, and the adhesive film is cut together with the semiconductor wafer by a cutting blade along planned dividing lines formed in the face-side surface of the semiconductor wafer, to thereby obtain the devices each with the adhesive film attached to the backside surface thereof (refer to, for example, Japanese Patent Laid-Open No. 2000-182995).
In recent years, electric apparatuses such as cellular phones and personal computers have been desired to be reduced in weight and size, and there is a demand for thinner devices. As a technology for dividing devices in a thinner form, a dividing technology called “dicing-before-grinding” has been put to practical use. The dicing-before-grinding method is a technology in which dividing grooves are formed in a semiconductor wafer in a predetermined depth (a depth corresponding to the finished thickness of devices) along planned dividing lines from the face side of the semiconductor wafer, and then the backside surface of the semiconductor wafer provided with the dividing grooves in the face-side surface thereof is ground to expose the dividing grooves on the back side, thereby dividing the semiconductor wafer into the individual devices. By the dicing-before-grinding method, the devices can be machined to have a thickness of 100 μm or below.
However, in the case of dividing a semiconductor wafer into individual devices by the dicing-before-grinding technique, the dividing grooves are formed in the semiconductor wafer in a predetermined depth along the planned dividing lines from the face side of the semiconductor wafer and, thereafter, the backside surface of the semiconductor device is ground to expose the dividing grooves on the back side. Therefore, a die-bonding adhesive film cannot be preliminarily attached to the backside surface of the semiconductor wafer. As a result, bonding to a die bonding frame the device manufactured by the dicing-before-grinding method has to be carried out while inserting a bonding agent between the device and the die bonding frame, which makes it very difficult to smoothly perform the bonding work.
To solve such a problem, there has been proposed a semiconductor device manufacturing method in which a die-bonding adhesive film is attached to the backside surface of the semiconductor wafer divided into individual devices by the dicing-before-grinding technique, the semiconductor wafer is adhered to a dicing tape through the adhesive film, and then the parts of the adhesive film which are exposed in the gaps between the devices are chemically etched away; besides, there has also been proposed a semiconductor device manufacturing method in which the parts of the adhesive film which are exposed in the gaps between the devices are irradiated with a laser beam through the gap from the face side of the devices, to remove the parts of the adhesive film which are exposed in the gaps (refer to, for example, Japanese Patent Laid-Open No. 2002-118081).
Incidentally, in order to cut the adhesive film by irradiation with a laser beam, the adhesive film has to be irradiated with a laser beam having such a wavelength as to permit absorption into the adhesive film (for example, 355 nm) and a mean output of about 2 W. Since the laser beam with a mean output of about 2 W is comparatively strong in output, irradiation of the adhesive film with the laser beam causes scattering of debris, and the scattered debris would adhere to the surfaces of the devices, thereby lowering the device quality.